Optical switch devices are used in various optical applications, such as optical communications. High speed optical switch devices often include phase shifters. In such optical switch devices, phase shifts (by electro-optic effects or magneto-optic effects) in one or more optical waveguides are adjusted to output different portions of input light from the optical waveguides. However, such optical switch devices require careful tuning of the phase shifts to achieve high contrast between on and off states.